Reaction jet torque compensation for helicopters



S. HILLER, JR

Sept. 13, 1949.

REACTION JET TORQUE COMPENSATION FOR HELICOPTERS Filed Nov. 25, 1946- 4 Sheets-Sheet 1 IN VEN TOR.

m 2 R M m m A Y v m S. HlLLER, JR

Sept. 13, 1949.

REACTION JET TORQUE COMPENSATION FOR HELICOPTERS Filed NOV- 25, 1946 4 Sheets-Sheet 2 m .K E .N M 4. E T a VL NL IM A Y L m 5 V. B

Sept. 13, 1949. s. HILLER, JR 2,481,749

REACTION: TORQUE COMPENSATION FOR HELICOPTERS Filed NOV. 25, 1946 4 Sheets-Sheet 4 INVEN TOR. STANLEY f/ILLER JR.

BY Qzw Z ATTORNEY-5 Patented Sept. 13, 1949 nnnoTroN JET TORQUE COMPENSATION T FQBHE QFFEE Stanley Hiller, Jr., Menlo Park, .Caliti, assignor to United Helicopters, Inc., Balg Alto, Calif., a qqrp rat on :Galifp Application Noyernher 25, 19%, e ri al 113,13 2 Claims. (01. 2.44f1m19) This invention relates to helicopters and concerned more particularly with the provision of a helicopter having improved apparatus and methods for compensating for the torque reaction of the wing structure.

In helicopters of the single wing type, the previous practice in effecting compensation for the torque of the wing is to provide an auxiliary propeller at the tail of the craft disposed to conipensate for the torque. This practice, while successful in operation, embodies several disadvan tageous features. The most m me'nt of these features are the extra weight entailed in mount ing the auxiliary propeller'at the tail of the aircraft and the extra load imposedon the'power plant for operation of this propeller together with the long drive shaft or drive connection which must be employed. This type of construction is further complicated by the necessity of mounting the rear torque-compensating propeller in a vertically displaced position so that it is not materially affected b'y the downwash of the wing struc ture and also imposes certain limitations on the overall length of the wing structure without excessive'length of the helicopteritself.

5.1 a ordan wi h h instant inv nti n t -bl nd to u s mn se ibn e s gle W s helicopters is solved byproviding an air or gas jt whose discharge is directed "from the tail of the 14s in th p ope di eqti n empe sate for the torque neaction. P re ferably this J et s di ec e t o h tunne -shape usel of the aircraft so that the p bpller for creatin the air jet i losely adjacent the powerplant and adrl t en pos tin t a ie i elso ssryesas a means for passing cooling air over theeh'gine. This results ina greater percentage ofeffe'ctive en i e s ava la f r flil'h l haw copter.

It isa general objectof the invention therefore to provide ajetcontrolledhelicopter.

A further object of the invention is toproyide theentire torque compensation fora single wing helicopter by means of anair or gas jet.

Another object of the invention is to provide an improved helicopter containing the foregoing objects in which the air jet is used for control of turning of the helicopter.

A further object of :the invention is to provide aghelicopter of thesingle wing type havinga simplified system of controls for maneuvering .the craft.

.Other objects and advantages ofthe invention will be apparent irom the followingdescription. of

a preferred embodiment thereof as illustrated in the accompanying drawings, in which:

Figure 1 is a schematic side elevational view partially in section of the helicopter embodying the invention.

"Figure? is an enlarged elevational view par.- tially in section of the wing mounting and control mechanism;

' Figure 3 is a bottom plan view of the universal mounting of the wing structure.

' Figure 4 is a fragmentary sectional view of a portion of the control mechanism taken .asindi catedloy the-line 44 in Figure 2. Figure 5 is a sectional plan View of the V jet tunnel or fuselage of the helicopter. Figure '6 is a front elevational View of the fuselage.

"Fig. -7 is a plan view taken along line 1-1 of Fig.1 showing the foot pedal cable connections. ReferringtdF-igure 1, there is illustrated a helicopter "including a body or frame 10 formed in"paft' of' tuhularstruts having landing gear ll mountedlthereon. Included in the body :structure is a fuselage or air tunnel l-2 suitably sup ported upon the tubular frame It. The helicopter includes also'a' power plant or engine I3 located immediately to the rear ofanopera'tors compartnint including a seat M, a. throttle control 16 forthe engine, a directional controlstick I], and foot'pedals' i8. Also, a drive head structure L9 .is provided which carries th wing structure 21, as describedhereinafter. The drive head structure includesa drive shaft 2 2 -w hich'is driven through a gear mechanism Z3,a drive shaft 24, and a clutch 26 from the engine l3. Referring to Figures -2 and 3, the two wingsections of the wing structure are each clamped at their innefendS-between bracket extensions 31 of amountin post'or stub shaft -32 which is seated in an annular recess 33 of .the supportinghub 3.4. l he J'nounting shaft 32 is provided with an annular flange '36 mating with a similar cfiange fifl of the supporting hub 3 2 to receive opposite clamping brack'ets 38 having securing and clampi'ng bolts 39 associated therewith. The supporting hub 34 is provided with opposite .boss'es Al apertured toreceiveopposite trunnions or .bearing portions 42 of a cross-shaped universal support eleinent 43. The cross-shaped supporting element 43 isalsoprovided with opposite shortertrunnion's or hearing portions 44 "which are journalle'd in opposite bo'sses'fifi of a forked top extensionof the drive shaft 22. 'Tt is seen from the above description that the wing :structure is mounted for .universal tilting 3 movement at the upper end of the drive shaft and that the universal mounting is encompassed by the wing structure and has its pivotal axes substantially coincident with the general plane of the Wing structure.

To effect control of the tiltin movement of the wing structure with reference to its universal supporting mounting, the wing hub 34 has secured thereon opposite trunnions 41 on which the bosses 48 of a pair of downwardly extending control arms 49 are journalled by means of suitable bearings. The depending arms 49 areintegrally formed with a ring section 5| of the wobble mechanism l9 which is secured by suitable cap screws on an inner part or ring 52 of the wobble mechanism about which an outer or stationary part 53 is journalled by bearings 54.

From the above description it will be seen that the wobble mechanism is pivotally connected to the wing structure about an axis at right angles to the longitudinal axis of the wing structure and coincident with the pivotal mounting axis of the wing structure on the drive shaft.

7 As previously stated, in general, the control stick I! is connected to the wobble mechanism l9 to exert a tilting effect thereon in both a fore and aft direction and in a lateral direction at right angles to the fore and aft direction. To effect the fore and aft adjustment of the wobble mechanism the outer part or ring 53 thereof n is connected by respectivecontrol links 56 to the horizontal transverse barof a T-shaped link 51 whose vertical leg 58 (Figures 2 and 4) is provided with an apertured boss 59 having its axis extending in a fore and aft direction and having laterally extending trunnions 6| journalled in a mounting bracket 62 on the frame of the helicopter. As seen in Figure 2, the rear end 63 of the control stick I! is journalled by bearings 64 within the boss 59 so that fore and aft movement of the control stick I! will cause pivoting movement of the control link 51, fore and aft movement of the connecting links 56, and consequently fore and aft tilting of the wobble mechanism l9.

- In order to control lateral movement of the wobble mechanism, the end portion 63 of the control stick I! is connected to a toggle mechanism including parallel links 66 and a V-shaped link 67, the latter of which is universally pivoted on the outer part 53 of the wobble mechanism. 7

The above described control mechanism is of .the type disclosed and claimed in my copending application, Serial No. 712,182, filed Nov. 25, 1946 for Helicopters.

The compensation of the torque reaction of the Wing structure, as previously stated, is effected by the creation of a laterally directed air jet at the tail of 'the aircraft. For this purpose the fuselage 12 (Figures 1, 5 and 6) is formed as a rearwardly tapering tunnel of sheet metal or the like provided with a laterally directedrear discharge opening 1| to which a series of verticallydisposed curved vanes or fins 12 lead the jet of air to its discharge so that a sidewise torque is produced by changing the direction of flow of air or other gas. At the entrance and of the tunnel a fan-type propeller 13 is journalled on the frame of the aircraft and is driven through a shaft M and a pulley drive I6 from the drive shaft 24. Immediately to the rear of the fan 13, an annular array of radially disposed air directing vanes T! are mounted extendingbetween the wall of the fuselage J2 and acentral cone-shaped support 18 Whose large endis'dis- -thereby. also increase its discharge pressure.

posed immediately rearwardly of the hub of the propeller or fan 13. The curvature of the vanes 17 is selected to exert a straightening efiect on the path of the air as it is discharged from the V propeller 13. If desired, the exhaust gases from r the engine or power plant l3 may be injected into the tunnel or fuselage l2 through a duct means I9 which extends from the power plant and to the tunnel and thereby also serves as a means for drawing cooling air past the engine. The exhaust gases not only add to the volume of gas in the tunnel, but also serve to heat the air in the tunnel to increase its volume and If desired, additional means such as a rearwardly directed flame may be employed in the tunnel for additional heating of the gas flowing therethrou'gh.

For use of the air jet in controlling turning of tion of the foot pedals- I8, the valve 83 can be 4 turned in either directionfrom this central position to cause turning of the'helicopter body to the right or left by increasing and decreasingthe effective volume of the jet in controlling torque reaction of the wing structure.

In operation of the helicopter with the wing structure rotating clockwise, as viewed from above a the craft, and with the propeller fan 13 in operation, the reaction from the jet discharge-at the tail of the aircraft compensates for the torque re v action of the wing structure on the helicopter body. In this connection the size, speed of rotation and pitch of the blades of the propeller fan are so selected withrespect to the characteristics of the wing structure and the torque reaction therefrom to provide straight ahead flight of the helicopter with the by-pass valve 83 in half open position. It will be noted that as the engine speed increases the speed of the wing structure and of the propeller fan increase proportionately to maintain a proper balance of the torque and jet reactions. By operation ofthe foot pedals I8 and further opening or closing of the by-pass valve 83, the eifectiveness of the jet discharge is changed to accomplish turning of the helicopter body in ac cordance with the directional movement of the by-pass valve 83. v While I have shown certain preferred embodiments of the invention, it"will be apparent that the invention is capable of further variation and modification and its scope should be limited only by the scope of the claims appended hereto.

I claim: f

1. A helicopter comprising a wing structure rotatable about an upright axis, an elongated gas tunnel having an inlet opening at its front end and a laterally directed rear dischargeopen ing in one side thereof, a blower adjacent the inlet opening of the tunnel and rotatable about an axis extending longitudinally of the'tunnel for creating a jet of gas through said tunnelfor discharge through said rear opening to compensate for the torque eifect of said wing structure, the side wall of said tunnel having a lateral by-pass opening adjacent said inlet opening through which some of said gas jet can be by-l assed for controlling turning of the helicopter, and an inwardly opening flap by-pass valve having one end pivotally mounted adjacent the rear of said bypass opening for controlling the by-pass of said gas jet through the by-pass opening.

2. A helicopter comprising a wing structure rotatable about an upright axis, an elongated gas tunnel having an inlet opening at its front end and a laterally directed rear discharge opening in one side thereof, a blower adjacent the inlet opening of the tunnel and rotatable about an axis extending longitudinally of the tunnel for creating a jet of gas through said tunnel for discharge through said rear opening to compensate for the torque efiect of said wing structure, the side wall of said tunnel having a lateral by-pass opening adjacent said inlet opening through which some of said gas jet can be by-passed for controlling turning of the helicopter, a plurality of radially disposed gas directing vanes mounted adjacent the rear of said blower and adjacent said by-pass opening for straightening out the gas flow from said fan, and an inwardly opening flap bypass valve having one end pivotally mounted ad- 6 jacent the rear of said by-pass opening for con trolling the by-pass of said jet through the by pass opening, said valve being positioned between adjacent vanes of said plurality of directing vanes. y I

STANLEY I-DILER, Jiti REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,697,770 Kreikenbohm Jan. 1, 1929 1,704,895 Higby Mar. 12, 1929 1,742,461 Cuddy Jan. 7, 1930 1,922,167 Leray Aug. 15, 1933 2,006,805 Gwinn July 2, 1935 2,365,328 Bell Dec. 19, 1944 2,369,652 Avery Feb. 20, 1945 2,419,604 Stanley Apr. 29, 1947 FOREIGN PATENTS Number Country Date 883,462 France Mar. 22, 1943 

